Door stop



FIG. 1 is a perspective view of a door stop showing my new design;

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof; and,

FIG. 4 is a right side view thereof, the left side being a mirror image.

The dashed lines are shown for environmental purposes only and form no part of the claimed design. The dotted lines shown in FIGS. 1 and 4 represent peripheries of the claimed design and form no part thereof. 

The ornamental design for a door stop, as shown and described. 